UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.170 Safari/537.36

Steps to reproduce the problem:
1. Have some javascript which generates base64-encoded favicons using canvas (so that we can show a red "number of unread messages" badge)
2. Update the favicon frequently, and keep the tab open for a while (we haven't found the exact reproduction steps yet, but it seems that putting your computer to sleep and waking it up might correlate).
3. Keep updating the favicon by setting the href attribute of <link rel="icon"> to a data url

What is the expected behavior?
The favicon continues updating

What went wrong?
At some point the tab gets into a "broken" state where all further updates to the favicon are ignored.

We can see in the developer tools that our code is continuing to update the href= attribute of the <link> element. But the tab's favicon no longer changes.

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: 66.0.3359.170  Channel: n/a
OS Version: OS X 10.13.2
Flash Version: 

This is possibly related to, but not the same as, https://bugs.chromium.org/p/chromium/issues/detail?id=792643 which deals with the bookmark bar.